A Study On Several Issues In The Chinese Calendar

In this paper,two groups of questions about the calendars in Qin and West Han period are discussed.The first group is of the intercalation modes of this period.With the principles of "the intercalation pattern of fixing solar terms prior to other patterns" and "important solar terms prior to other solar terms",this paper puts forward a new methodology to calculate the intercalation modes of the three calendars of Qin and early Han,the methodology which is stricter than previous ones.The conclusions are: the intercalation mode of the former two calendars must be among "fixing Winter-solstice in the 11 th month" and "fixing Winter-solstice between the new moon of the 11 th month and that of the 12 th month";the most possible intercalation mode of the later calendar is "to intercalate when one of the months between the beginning of the 1st month and the end of the 12 th month has not a Zhong-qi within it".The investigations in related fields are suggested to illustrate more sufficiently and to have methodologies clarified when it is necessary.The second group is of the deviation of Taichu Calendar and the derivation of its epoch time.In its beginning,the time points of new moons of Taichu Calendar have an average deviation of 7 hours and 13 minutes later than astronomical conditions,and the time points of winter solstices have an average deviation of about 1 day and 4 hours later,all of which are acceptable to the calendarists in that period.The accumulation of deviation of Taichu Calendar was not observed,and the tropical year cycle and the lunation cycle of Sifen Calendar and Taichu Calendar were not distrusted,because the calendars before Taichu Calendar were regarded as inaccurate from its beginning.The solar factor of the epoch time of Taichu Calendar is basically derived from the calendar before it,and the application of its lunar factor is due to both accuracy and the idea of heavenly mandate.It is impossible for the calendarists in that period,who adopted the compilation method of Sifen Calendar,to acquire another epoch time which might make Taichu Calendar more accurate and at the same time retain in it their idea of heavenly mandate,which entails that Jia-zi date,midnight,new moon and winter solstice coincide,in which sense the actual epoch time was inevitably adopted.